Electric alarm release and timing device



Aug. 29, 1967 A. DELADERRIERE 3,339,934

ELECTRIC ALARM RELEASE AND TIMING DEVICE Filed Oct. 21, 1965 2 SheetsSheet 1 United States Patent 3 Claims. 201. 200-38 The present inventionrelates to an alarm release and timing device for electric timeappliances.

In time appliances using an electric dry-cell as energy source, thealarm system actuated by an electromechanical mechanism is generallyconstituted by a means consuming much energy.

In view of this large energy consumption, it therefore seems valuable tobe able to limit the alarm functioning time and it may be consideredthat in practice the functioning of the alarm during one minute is quitesufficient.

Moreover, the addition of an ancillary mechanism such as an alarmrelease, very often introduces into the appliance an element whichdisturbs the setting system.

One aim of the present invention is to obviate this disadvantage whilesatisfying the abovementioned condition.

Another aim of the invention, which does not attempt to obviate classicbasic faults, is to create an assembly of very small dimensions, whichis of great interest for the development of the future small electricalarm clock.

The invention therefore has as its objects an electrical alarm releaseand timing device which guarantees a minimum consumption of energy whichprovides great functional dependability due to forceful and quick-actingfriction contacts which practically eliminates the effects of therelease disturbance on the setting means, and which allows said deviceto have extremely small dimensions.

The device according to the invention comprises, on the one hand, a leafspring secured to the hour wheel of the movement of the alarm clock andcut to form two helicoidal contact strips and, on the other hand, arelease assembly freely rotating about the spindle of said hour wheeland comprising: an index wheel, controlled from outside the applianceand driving the assembly in rotation in the opposite direction to thatof the hour wheel, said index wheel being in permanent contact with afalse-plate which is earthed; an intermediate annular part made ofinsulating material and an upper annular metal part with which an alarmstop lever may enter into contact, said lever being maneuverable fromoutside the appliance and communicating with the alarm which isconnected to one pole of an electric dry-cell, the other pole of whichis connected to the earth; said upper part being provided with an insideradial projection placed on the trajectory of one of the contact stripsof said leaf spring while the other strip of the latter may enter intocontact with a helicoidal projection provided in the index wheel, thecontact of the first strip with the radial projection of the upperannular part being delayed, in relation to the contact between thesecond strip and the projection of the index wheel, by a ramp providedin the insulating intermediate annular part and overlapping said radialprojection in order to limit the contact according to an annulardistance determined by the relative adjustment of the three partsconstituting the abovementioned release assembly.

The ramp provided in the intermediate annular part made of insulatingmaterial causes the first strip to drop suddenly onto the projection ofthe upper annular part, thus creating a forceful contact between the twoelements, this contact being followed, after sliding of the strip onsaid projection, by a second dropping of the strip beyond the latter,which causes a sudden breaking of the contact.

The angular distance created between the upper annular part and the rampof the intermediate insulating part governs the overlap of theprojection of said upper annular part and determines the period offunctioning of the alarm.

The index wheel is provided with an annular rib sliding on a false-plateconnected to the earth of the alarm clock and thus ensuring constantcommunication between said earth and the projection of the index wheel.An embodiment of said device is described below, by way of simplenon-limitative example, with reference to the accompanying drawings, inwhich:

FIGURE 1 illustrates the elements constituting'the device seen inelevation;

FIGURE 2 illustrates the device seen from above;

FIGURES 3 and 4 illustrate the device in two functional positions.

The device itself is constituted by a leaf spring *1 cut to form twostrips 1a and 1b and to fit the hour wheel 2 of the movement of thealarm clock, which effects one complete rotation in twelve hours in thedirection of the arrow 7 in FIGURE 2. The spring 1 is firmly secured tosaid wheel and therefore effects an identical rotation.

The spindle 3 of the wheel 2 pivots in the body (not illustrated) andthe base plate 4 of the alarm clock.

There may rotate freely about the spindle 3 an index wheel 5 bearing thepointer which indicates on the dial the time of the alarm release. Saidwheel 5 can only move in the direction indicated by the arrow f inFIGURE 2; it is controlled from outside the appliance through the mediumof a pinion 6 which meshes with external toothing on the wheel 5. Thelatter has a helicoidal 5a situated on the trajectory of the strip 1b ofthe spring 1.

On the index wheel 5 is fixed an annular part 7 made of insulatingmaterial, bearing in its turn an annular metal part 8 constituting thesupply crown and including a projection 8a adapted to enter into contactwith the strip 1a of the spring 1.

The end of a lever 9 may be brought into contact with with said crown 8,said lever pivoting with a spindle 10 passing through an insulating part11 fixed to the base plate 4. The lever 9 is maneuverable by means of ahandle 12 situated outside the appliance and constitutes the alarm stopof the latter.

The spindle 10 is maintained in constant pressure contact with a strip13 connected by a wire 14 to an alarm 15 connected in turn to thepositive pole of a dry-cell 16 by a wire 17. The negative pole isconnected to the earth of the appliance by a wire 18. The strip 13therefore allows the spindle 10 of the lever 9 to pivot while ensuringan excellent frictional contact. The index wheel 5 is provided with anannular rib 5b which rests on a false-plate 19 provided with pillars 20receiving screws 21 which fix it to the base plate 4. It is seen thatthe wheel 5 thus, by its rib 5b, ensures an earth return by constantfriction on the false-plate 19.

The insulating part 7 is provided with a ramp 7a adapted to overlap theprojection 8a of the supply crown 8.

The functioning of the device will be better understood on examinationof FIGURES 3 and 4.

FIGURE 3 illustrates the device some moments before the release of thealarm, that is at 21600 (a radians) seconds 21600 (B radians) secondsThis angle is accurately'determined during the fitting of the part 8 tothe part 7.

It is seen that the passage of the current is therefore establishedduring the alarm functioning time, from the positive pole of thedry-cell 16, through the wire 17, the alarm 15, the wire 14, the strip13, the spindle 10, the lever 9, the part 8 and its projection 8a, thestrip 1a, the strip 1b, the projection 5a of the index wheel 5, the rib5b of the latter and the false-plate 19 which is earthed.

During this time, the contacts are essentially frictional and guaranteeself-cleaning of the contactsurfaces, always a primordial condition ofproper functioning, whatever the nature of the contacts.

It is to be noted that between the two positions illustrated in FIGURES3 and 4, the larger release strip 1a drops from the upper face of theramp 7a to that of the projection 8a.

The developed length of said strip 1a and the dropping height are suchthat the pressure variations are very small despite the variations infriction which may exist between the strip 1a and the ramp 7a as well asbetween said strip and the projection 8a. Moreover, it should be notedthat the projection 5a of the wheel 5 has a slight helicoidal curve andthus performs two main functions:

(a) It ensures automatic compensation of the play of the drive gearingof the hour wheel 2 during the alarm release: in other Words, it avoidsany partial reduction of the angle 5 at the moment of the drop in termsof time and in a random manner;

(b) It maintains during the alarm functioning time a sufficient earthreturn contact pressure and the self-cleaning of the earth returncontact.

Moreover, this pressure rises slightly during the alarm functioning timeand as its opposing torque increases, compensates to some extent thedecreasing opposingtorque exerted on the large strip 1a at the time ofthe first drop which releases the alarm.

When the spring 1 has passed through the angle 5, the second drop stopsthe alarm and there remains the angle 'y to be passed through by thesecond strip 1b, which constitutes the safety angle.

It should be noted that this release principle aims at the creation ofan extremely fiat assembly.

What I claim is:

1. In an alarm release device for electric time appliances, theimprovement comprising: a driven hour wheel rotatably mounted on aspindle, a bifurcated leaf spring having two helicoidal strips securedto said hour wheel, a release assembly freely rotatable about saidspindle and comprising an index wheel provided with means for drivingsaid assembly in the opposite direction to that of the hour wheel, saidindex wheel having a lower part in permanent contact with a groundedfalse-plate and an upper annular metal part insulated from ground by anintermediate annular part made of insulating material, an alarm stoplever movable into contact with said upper part for connecting saidalarm to a power source, said upper part being provided with an insideradial projection placed on the trajectory of one of the contact stripsof said leaf spring while the other strip of the latter contacts ahelicoidal projection provided on the lower part of the index wheel, thecontact of the first strip with the radial projection of the upperannular part being delayed in relation to the contact between the secondstrip and the projection of the index wheel by a ramp provided in theinsulated intermediate annular part and overlapping with said radialprojection in order to limit the contact according to an angulardistance determined by the relative adjustment of the three partsconstituting the above mentioned release assembly.

2. A device according to claim 1 wherein said ramp of the intermediateinsulating part is shaped and disposed to cause the sudden dropping ofthe first contact strip onto the projection of the upper annular part,thus ensuring a forceful contact between the two elements, said contactbeing followed, after sliding of the strip on said projection by asecond dropping of the strip beyond the latter, which results in asudden opening of the contact and wherein the overlap of the projectionof said upper annular part with the ramp determines the period offunctioning of the alarm.

3. A device according to claim 1 wherein the index wheel is providedwith an annular rib sliding on said false-plate connected to ground ofthe alarm.

References Cited UNITED STATES PATENTS 2/1890 Straight 340309.1 7/1966Neif 200-166

1. IN AN ALARM RELEASE DEVICE FOR ELECTRIC TIME APPLIANCES, THEIMPROVEMENT COMPRISING: A DRIVEN HOUR WHEEL ROTATABLY MOUNTED ON ASPINDLE, A BIFURCATED LEAF SPRING HAVING TWO HELICOIDAL STRIPS SECUREDTO SAID HOUR WHEEL, A RELEASE ASSEMBLY FREELY ROTATABLE ABOUT SAIDSPINDLE AND COMPRISING AN INDEX WHEEL PROVIDED WITH MEANS FOR DRIVINGSAID ASSEMBLY IN THE OPPOSITE DIRECTION TO THAT OF THE HOUR WHEEL, SAIDINDEX WHEEL HAVING A LOWER PART IN PERMANENT CONTACT WITH A GROUNDEDFALSE-PLATE AND AN UPPER ANNULAR METAL PART INSULATED FROM GROUND BY ANINTERMEDIATE ANNULAR PART MADE OF INSULATING MATERIAL, AN ALARM STOPLEVER MOVABLE INTO CONTACT WITH SAID UPPER PART FOR CONNECTING SAIDALARM TO A POWER SOURCE, SAID UPPER PART BEING PROVIDED WITH AN INSIDERADIAL PROJECTION PLACED ON THE TRAJECTORY OF ONE OF THE CONTACT STRIPSOF SAID LEAF SPRING WHILE THE OTHER STRIP OF THE LATTER CONTACTS AHELICOIDAL PROJECTION PROVIDED ON THE LOWER PART OF THE INDEX WHEEL, THECONTACT OF THE FIRST STRIP WITH THE RADIAL PROJECTION OF THE UPPERANNULAR PART BEING DELAYED IN RELATION TO THE CONTACT BETWEEN THE SECONDSTRIP AND THE PROJECTION OF THE INDEX WHEEL BY A RAMP PROVIDED IN THEINSULATED INTERMEDIATE ANNULAR PART AND OVERLAPPING WITH SAID RADIALPROJECTION IN ORDER TO LIMIT THE CONTACT ACCORDING TO AN ANGULARDISTANCE DETERMINED BY THE RELATIVE ADJUSTMENT OF THE THREE PARTSCONSTITUTING THE ABOVE MENTIONED RELEASE ASSEMBLY.